When my father, Rondal Partridge, was 17, he began working for Dorthea Lange, best known for her photograph, Migrant Mother. He worked in Dorothea’s darkroom, packed her camera bags, and drove her up and down the back roads of California. “Slow down, Ron, slow down,” she would insist as they crept along at twenty miles an hour. When they saw something interesting, they stopped: a migrant camp, a piece of broken-down farm equipment, people in a field picking crops. Dorothea took thousands of pictures for the Farm Security Administration, trying to capture the experiences of the dust bowl refugees who had drifted out to California, looking for work.

“Their roots were all torn out,” Dorothea said about the migrants. “I had to get my camera to register the things about those people that were more important than how poor they were—their pride, their strength, their spirit.” Ron and Dorothea walked into camp slowly, her limp from childhood polio immediately setting the migrants at ease. They knew she understood being struck down by adversity. She sometimes asked for a glass of water and drank it very slowly, letting people get used to her presence. Then she set her camera on a tripod, and often began photographing by asking a child to pose for her.

One boy stood in front of her camera, his stubbley head looking like it had been shaved for lice, his face grubby, but a look of tender pride in his eyes as he held up two fat, squirming puppies. Dorothea titled the photograph Migrant People (1938), letting the boy represent the many difficulties and strengths of the migrant workers.

Recently, I asked my father if he saw many dogs when he was on the road with Dorothea. He shook his head. “Often there wasn’t enough food for the kids,” Ron said. “Not many migrants brought a dog.”

Despite their meager resources, a few migrants did bring their dogs. Dorothea included them in her photos, alongside their owners in Fruit Tramp (1935) and Spanish Americans (1943). It’s easy to imagine how important these dogs could be, as the refugees wandered around with their “roots all torn out.” The feel of dogs’ silky ears, the trusting look in their eyes, the smell of grass and dust and sun in their coat: All this must have been reassuring in a world suddenly turned over.

In the late ’30s and early ’40s, Dorothea took several trips out of California. Once again we see her posing a child with his dog in Elm Grove, Okla. (1938). The contrast with the migrant boy and his puppies is striking. The boy wears patched and worn clothing, but he looks clean and well-fed. The Depression had not forced his family onto the road. In Iowa, Small Town Life (1941) as the Depression is easing, we see a lesser-known version of one of her popular photographs. It includes a farmer’s dog who has wandered into the frame. Alert and bright-eyed, it’s easy to imagine he just rode into town in the back of a pickup truck, happy to be with the other farmers he knows from previous trips.

In fields and camps and small towns, Dorothea did exactly what she set out to do: photograph the strength and resilience of the American spirit. And side-by-side with these courageous people are their beloved dogs.